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SURVIVAL IN RELATION TO BROOD‐SIZE IN TITS
Author(s) -
LACK DAVID,
GIBB JOHN,
OWEN D. F.
Publication year - 1957
Publication title -
proceedings of the zoological society of london
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.915
H-Index - 96
eISSN - 1469-7998
pISSN - 0370-2774
DOI - 10.1111/j.1096-3642.1957.tb00326.x
Subject(s) - brood , avian clutch size , nest (protein structural motif) , biology , ecology , clutch , zoology , seasonal breeder , reproduction , biochemistry , physics , thermodynamics
SUMMARY1 In most years the mean weight of nestling Great and Blue Tits was lower in larger than smaller broods, but it was similar in 1948, when food was exceptionally abundant. 2 In most years, the commonest clutch of the Great Tit was nine or ten, and the average number of young surviving per brood was highest from broods of nine or ten. But in 1947 and 1948, when food was unusually abundant, clutches were unusually large and survival was as high from broods of above average size as from those of average size. The results for the Blue Tit seemed similar. 3 Few Great Tits have late broods, and, as compared with normal broods, the clutches are smaller, the young weigh less, have higher losses in the nest and survive much less well after leaving the nest. Much the same holds for the Blue Tit. 4 These findings accord with the view that the normal breeding season of the Great and Blue Tits is that when they can raise most young, and that their clutch size is in general adapted to the number of young that they can raise.